Torpedo steering mechanism



` March 14, 1961 :.H.'1'|1\1DAL 2,974,621

' ToRPEDo STEERING MECHANISM 4 Sheets-Sheet 1 Fild May 8, 1947 INVENTORATTORNEY March 14, 1961 c. H. TINDAL 2,974,621

TORPEDO STEERING MECHANISM Filed May 8, 1947 4 Sheets-Sheet 2 QD 55 /h'u 42`\` FIG. 5 43 ATTORNEY March 14, 1961 c. H. TINDAL 2,974,621

TORPEDO STEERING MECHANISM Filed May 8, 1947 4 Sheets-Sheet 3 lNvENToRATTORNEY TORPEDO STEERING MECHANISM Charles H. Tindal, 'State College,Pa., assigner to the United States of America as represented by theSecretary of the Navy Filed May 8, 1947, Ser. No. 746,805 3 Claims. (Cl.114-44) This invention relates to guided missiles, such as torpedoes,and especially to the steering mechanism for such missiles wherein theposition of a control surface or steering member for guiding themissile, e.g. the rudder, is governed either by a gyroscope or inaccordance with acoustic signals emanating from a target.

By this invention there is provided a steering system for torpedoeswherein, initially after the torpedo is launched, the control surface isgoverned exclusively by a gyroscope for a predetermined period tomaintain the torpedo traveling in a preassigned direction, for example,in the direction in which it is launched. After the torpedo has traveledsome distance from the launching vessel, the steering system is thenconditioned so that the position of the control surface may betransferred from gyroscopic influence to control by a signal translatingsystem that is responsive to signals emanating from a target, such aspropeller and ship noises, the said signal translating system beingeffective to so position the control surface as to guide the torpedo tothe target.

The signal translating system per se while forming no part of thepresent invention may comprise, for example, a pair of hydrophonessensitive to compressional waves, or acoustical vibrations within apredetermined frequency range, mounted on the torpedo in a commonhorizontal plane but on opposite sides of the center line, so that thepercentage diierence in the intensities of the outputs of the twohydrophones is a measure of the bearing of the target relative to thetorpedo. As later described in greater detail, the hydrophone outputsare amplied, rectied and applied to a comparison circuit, so that thecomparison circuit output may be utilized for controlling the azimuthalposition of the torpedo in accordance with the percentage difference inthe intensities of the signal on the hydrophones.

The present invention in one important aspect deals with thesimplication of the operative linkage between the gyroscope and thetorpedo steering engine, a part of this operative linkage also beingutilized to eiect control in response to acoustic signals; `and involvesalso the basic combination embraced in the idea of conditioning thetorpedo steering system for control in response to both gyroscope andacoustic signals, only after a run of predetermined duration duringwhich the torpedo steering system is exclusively under control of thegyroscope.

The 'importance of this concept of this invention will be appreciatedonce it is considered that at the beginning of the run, whether thetorpedo is launched from an airplane or from a submarine, the noiselevel created by the launching is inevitably very much higher thannormal running noise of the torpedo. Moreover, electronic devicesemployed in the steering system, and operating by virtue of thermionicemission of electrons require time to attain their optimum operatingtemperature. For these and other reasons that will be apparent later,this invention provides means for maintaining the torpedo underexclusive `gyroscopic control at the start of the Patented Mar. i4, tii

run; and at a predetermined time thereafter conditioning the steeringsystem for transfer to acoustic response.

lt should be understood that under the provisions of this invention noimmediate transfer to acoustic response is effected, that is, thetorpedo continues to run under gyroscope control until it reaches apoint in its path where the target signal level at the hydrophones is ofat least a preassigned magnitude. This transfer as determined by themagnitude of signal level entails inherently a restriction of the rangeat which the rudder may be connected to control in accordance withtarget signal. This follows from the fact that the transfer element mustbe set to allow for torpedo self noise and ambient submarine signals sothat transfer can be eiected only when the total signal level issomewhat above the target signal level for which the signal transmittingsystem is capable of controlling the rudder in accordance with signalsreceived by the hydrophones in the presence of self noise and ambientsubmarine signals. This is achieved, for example, by providing asuitable relay in the output circuit of the amplier for the signalreceived by the hydrophones. This relay is set to function whenever thenoise level to which one or both of the hydrophones are subjectedreaches a threshold value; that is, the energizing circuit for thisreiay may be connected to the amplified output of one hydrophone, or tothe ampliiied output of the differential signal level.

ln accordance with another feature of the present invention means areprovided for preventing return to gyro-| scope control once the noiselevel reaches the aforesaid threshold value. This feature of theinvention is achieved by providing a holddown relay and permitsre-attack by the torpedo in the event of an initial miss of the target.For example, if the torpedo should miss the target on the initial run itwill commence to circle either to the right or left, depending upon thedirection in which the rudders were displaced lby the last receivedsignal, and will continue to circle until it again picks up the targetnoise. This action for `re-attaci; would not be effected if gyroscopecontrol were re-established upon reduction of available acoustic level.

it has been the practice prior to this invention to utilize mechanicallinkages entirely, between the gyroscope and the control valve of theazimuth steering engine. The present invention has simplilied thismechanical linkage by incorporating a suitable electro-magnetic meansfor actuating the control valve of the steering engine, and selectivelyenergizing the said electro-magnetic means in response to a courserestoring force initiated by the lgyroscope of the torpedo. This hasbeen particularly advantageous in adapting the torpedo to acousticcontrol since the same electro-magnetic component may be utilized alsoto actuate the steering engine in response to acoustic signals.

lt is apparent from the foregoing, therefore, that it is a primaryobject of this invention to simplify the operating linkage between thegyroscope of a torpedo and its azimuth steering engine.

it is also an object of the invention to provide a steering systemwherein control may be subject to response to acoustic signals as wellas gyroscopic action.

Another object of the invention is to provide means responsive to apredetermined acoustic level for effecting a non-revertible transfer oftorpedo steering control frorn gyroscopic response to acoustic response.

lt is a still further object of this invention to provide an enablingdevice which, after a predetermined run of the torpedo, will conditionthe steering system thereof so that transfer from gyroscopic control toacoustic control may be effected when the torpedo is subjected to asignal of predetermined intensity. Prior to actua- Vside for receivingthe pallet holder.

tion of the enabling device the torpedo is exclusively under gyroscopicsteering control.

Other objects and advantages of this invention will be apparent yfromthe following description of a preferred embodiment of the inventionillustrated in the accompanying drawings, wherein Fig. 1 is a plan viewin perspective of the gyroscope assembly, showing the enabling deviceand the electromagnetic means for actuating the steering engine inrespouse to the course restoring force of the gyroscope;

Fig. 2 is an elevational view in cross-section of the enabling device,the section being taken on lines 2 2 of Fig. 4;

Fig. 3 is a plan view in perspective showingthe brackets for mountingthe electro-magnetic means on the gyroscope housing;

Fi-g.- 4 Vis aVY plan View partly in cross-section Y'ofV the assemblyshown in Fig. 1, butY including the steering t engine;

Fig. 5 is a longitudinal elevational view of the electromagnet and'steering engine assembly, showing the electromagnet in cross-section,the section being taken on lines 5 5 of Fig. 4;

Fig. 6 is a perspective elevational side View partly in cross-sectionshowing the entire steering assembly;

Fig. 7 is a diagrammatic view illustrating the operation of the improvedsystem for controlling the position of the steering member, e.g.,rudder, in response to course restoring lforce of the gyroscope; and,

Fig. 8 is a schematic electrical circuit diagram showing the electricalconnections involved in the steering system of this invention.

Referring now to the drawings and particularly to Figs. 1, 4, 6 and 7the gyro-mechanism indicated generally at 10 in the drawings comprisesthe housing 11 in which the gyroscope (not shown) is contained andinitially driven to its required spinning velocity by the tooth rotor12. 'This housing is shown assembled on a large base plate 13 which isadapted for mounting in the torpedo without affecting adjustment of theindividual mechanisms assembled thereon. The lower end off the gyroscopehousing is secured to the base plate 13 and has its upper end closed bya suitable cover plate 14 of bronze, for example, on which is assembledthe pallet mechanism indicated generally in the drawings at 15.

The pallet mechanism 15 comprises the means for utiliZing the directiveforce of the gyroscope to selectively energize the electro-magnetindicated generally at 43. The main function of the pallet mechanism isto transmit movement from the gyroscope to the selective ener- 4 bevelgear 28 to impart a reciprocating motion to the slide Ztl and palletblade 21. Although not shown in the drawings the slide Ztl is` biasedtoward the cam surface 26 by means ofa pair of springs each one of whichpresses (the pressing is done through plungers which barely show in Fig.4), against the projecting surface of theT.

The slide 2lb is retained in the channel 215 of the top cover plate bymeans of the slide'cover 30 which is suitably machined to fit over thepallet slide. This cover is provided with two posts 31 and 32 whichserve as pivots for the pallet pawls 33 and 34. These pawls arecross-connected by the switch operating bar 35 which is shown Secured bymeans ofY screws `to the adjusting links 36 and 37 which are attached tothe pawl arms 33 and 34 by suitable pins fitted to the ends of each ofthc pallet pawls. r

The switch bar. 35 is shown provided with an offset portion 38positioned between the operating buttons 41 and 42 of their respectivemicro-switches 39' and 40 which are mounted on the top plate 14 so as toface each other. Thus it will be seen that when the cam 26 is in aposition to permit the pawl y16 to be moved toward the gyro cam plate 18by the spring loading applied to the pallet slide 20, and the torpedocourse diiers on either side of the proper course or reference axis ofthe gyroscope, one of the pawls will have moved into line with and willcontact the cam surface 17, imparting a slight rotary movement to thepallet shaft 19 with a consequent angular displacement of the palletblade 21. Upon further rotation of the cam 26 the slide 20 will beadvanced on the top cover plate to move the pawls 16 away from thegyroscope cam 18 and to move the pallet blade 21 into contact with oneof the pawls 33I or 34 which through the connecting linkage with theswitch operating bar 35 will operate one or the other of themicro-switches 39 or 40 to energize either end of the double solenoidelectro-magnet 43. It is to be observed that movement of the pawl 16toward the gyroscope cam 1S when the course of the torpedo coincideswith the gyro axis will cause the pawls to straddle the cam surface 17,in which position the pallet blade 21, when moved by the cam 26 to aposition away from the gyroscope cam plate will pass between the palletpawls 33 and 34.

The electro-magnet 43 is attached to the base plate 13 by means of thebracket 44 and as shown in Fig. 5 comprises a pair of axially alignedand differentially operated gizing means for the electro-magnet withoutsetting np a vdisturbing torque that will cause the. gyroscope toprecess. This is accomplished by -eifecting an intermittent lightContact of the small cam pawls 16 (Fig. 7) with the cam surface 17 ofthe cam plate 18 which is rigidly secured to the top of the outer gimbalring (not shown) of the gyroscope. The cam pawls 16 are iitted andpinned to the pallet shaft 19 which is rotatably supported in a verticalbearing sleeve of a pallet holder, the sides of which are machined witha sliding it for insertion in the pallet slide 29. The pallet whichcomprises the blade 21 extends from a hub 22 that is drilled to lit overthe upper end of the shaft 19 to be there clamped in place. The slide 20is shown in the form of a T-shaped member having a channel 23 machinedon its upper A large hole 24 is drilled through the slide for insertionof the bearing sleeve of the holder with sucient clearance to permitlimited adjustment of the pallet holder in the slide. The bottom andsides of the slide 211 are machined to a sliding fit in the channel 25of the top cover plate 14, so that T end of the slide bears against thecam surface 26 formed on the bevel gear 27. The cam surface 26 and bevelgear 27 are 4rotatably mounted on the stud shaft 29 and driven by thetorpedo propeller shaft through the solenoids 45 and l46, each beingwound about their respective cores 47 and 48 and encased within a metalsheath 49. The axial length of each core is less than the axial lengthof its respective solenoid to provide a space within the central portionof the electro-magnet for supporting an yarmature 50 so that it is freeto move in either 'of two directions, to close the air gap between itand a kysteering engine valve stern 54.

As shown in Fig. 6 the steering engine S5 is attached to the right handside of the gyroscope housing 11 with two holding screws, the recess 56(see Fig. 1 being machined in the Walls of the steering engine block 57to t the rectangular lug 58 extending from the gyrosc'ope housing. Theengine block 57 has a cylindrical bore 58 machined therein for theinsertion and movement therein of the piston S9. The piston 59 and rod60 (see Fig. 5) are shown machined of one piece, with an end of the rod60 protruding through a stuing box 61 and gland 62 in threadedengagement with the forked connection 63 for connection to the steeringrod 64 (see Fig. 6). The rod `64 in turn is connected with the verticalsteering mdders 64a (Figs. 6 and 7), which rudders are anexemplitication of the control surface herein contemplated.

The piston v59 is operated by the admission of air under pressure ateither side thereof, the ilow of said air being governed by a valve 65comprising a sleeve 66 and cooperating valve stem 54. The sleeve 66 isiitted into a hole 67 that is drilled into the engine block parallelwith and below the engine cylinder to provide a valve chamber having thenecessary annular grooves, valve seats and ports for air entry andexhaust as is clearly shown in Fig. 7. The valve stem is shown in Figs.5 and 7 machined with three grooves, the center groove 68 controls theflow of air into the cylinder; and the outer grooves 69 and 69 directthe ow of exhaust air.

Referring again to Fig. 7 it will be noted that air is furnished throughthe valve casing'into the central groove 70 machined in the sleeve 66.Holes 71 are drilled through the sleeve extending from the bottom of thegroove to permit air to pass to the central groove 68 of the Valve 65and thence upon displacement of the valve in either direction into theworking end Iof the cylinder 58 through openings 72-73, or 74-75,drilled in the sleeve, and their respective communicating grooves 76 and77.

It is thus apparent that the steering engine 55 is operated from thepallet pawls 33 and 34 electrically in response to a course correctingforce from the gyroscope. However, in accordance with a principal objectof this invention and as illustrated in Fig. 8, provision is made tosubstitute, at a predetermined acoustic signal level, anacoustic-control for the gyro-control described above, it being apparentfrom the Iwiring diagram of Fig. 8 that the solenoids 45 and 46 areselectively energized by the acoustic signal system to control thesteering engine.

The particular acoustic signal system for selectively energizing thesolenoids is not a part of the present invention and is disclosed onlydiagrammatically, it being clearly understood however that there are anumber of such systems known to the art capable of achieving thispurpose, and readily adaptable to the combination herein described.

There is also shown diagrammatically in Fig. 8 at 78 an enabler switch(indicated diagrarnmatically in Fig. 8 oy the single pole double throwswitch) which maintains the solenoids `45 and 46 exclusively undercontrol of the gyroscope for a predetermined run of the torpedo. Whileany number of devices known to the prior art may be utilized to delayconditioning of the operating circuit for transfer from gyroscope toacoustic response, one highly successful device is illustrated in Figs.l, 2, 4, and 6, and designated generally by reference numeral 78. Thisdevice comprises a locking type of micro switch 80 adapted to beoperated by the cam 81. The mechanism (see Fig. l) for driving this camincludes a shaft 82 which is `driven by the bevel gear 83, which gear inturn meshes with the cam bevel gear 27, and which carries the Worm 84.This worm drives the wheel 85 and through an additional worm and wheelreduction 86-S7 (see Fig. 4) drives the cam 81. The surface of the camupon a predetermined rotation lbears against the operating button S8moving the switch arm into a position of locking engagement with thecontact 89 to condition the circuit for transfer yfrom gyroscope toacoustic control. In the displaced position the switch arm can bereturned only manually by the reset button shown at 90 in Fig. 2.

Referring again to Fig'. 8 it will be observed that after the enablerswitch 7 8 is displaced from the position shown to close the circuitleading from contact 89 the solenoids 45 and 46 may be energized by thecircuit controlled by the gyroscope-actuated micro switches 39 and 40(indicated diagramrnatically at 79) or by the acoustic signal systemoperating the relay indicated at 91, dependent upon the condition of therel-ay 92 which determines whether the gym-actuated microswitcharrangement 79 or the swinger contact of relay 91 will be connected incircuit to operate the solenoids 45, 46. It should be noted thatenergization of the relay 92 is controlled by the relay 96 which in turnis controlled by a suitable signal intensity responsive circuit, so thatthe relay 92 becomes energized only when an acoustic signal ofpredetermined level and duration is received by the hydrophones.Thereafter the relay 92 is mechanically locked in thrown position as bya catch 93 so that it cannot return to the position shown which wouldpermit a return to gyroscope control. t should further be noted thatwhen relay 92 has become energized, the swinger contact of relay 91completes the circuit to either solenoid 45 or 46, dependent upon thecharacter of the signal applied to the D.C. ampliiier, thus effectingtorpedo steering either to port or to starboard dependent upon therelative direction of the target which gives rise to the signal asreceived by the R and L (right and left) hydrophones.

In the illustrated signal translating system, the input circuit to theA.C. amplifier and automatic volume control is through the commutatorswitch so that the preamplied output signal from one hydrophone and thenthe other serves Kas the input. The rectied D.C. outputs are alternatelyapplied, by means of the second commutator switch and in accordance withconventional technique, to the condensers 94 and 95 shunted by bleederresistances 97 and 9S and connected in series opposition in aconventional signal comparison arrangement. Thus each condenser is inturn energized for a short time in accordance with the amplied (D.C.)output of its respective hydrophone. Accordingly, the signal applied tothe D.C. amplifier is in effect la measure of the percentage differencebetween intensities of the signals on the two microphones.

While a particular and preferred embodiment of this invention has beendisclosed it is understood that such disclosure is for the purpose ofillustration only, and not for the purpose of limitation, reference forthis latter purpose being had to the appended claims.

I claim:

1. In combination with a propulsive torpedo: torpedo steering meansincluding a pair of opposed solenoids and an energizing source forproducing a torpedo turn in a direction corresponding to selectiveenergization of said soleuoids; a course gyroscope and switchesselectively actuated thereby in accordance with deviation of the torpedofrom a predetermined course; rst and second switch means;electro-acoustic means, including a pair of hydrophones for sensingacoustic target signals, and operating said tirst switch means from arst condition to a second condition in accordance with the direction,relative to torpedo heading, of the target which gives rise to saidacoustic target signals; said electro-acoustic means further operatingsaid second switch means from a rst condition to a second condition inresponse to sensing an acoustic target signal exceeding a predeterminedthreshold amplitude; an enabler switch; initial run control means foroperating said enabler switch from a iirst condition to a secondcondition after expiration of a predetermined torpedo run interval; saidenabler switch in it-s first condition connecting the energizing sourceand solenoids of said steering means in circuit with said gym-actuatedswitches for exclusive control thereby until expiration or" saidpredetermined interval; said enabler switch in its second conditionconnecting the solenoids through said second switch means in the tirstcondition thereof, before operation of said second switch means inresponse to an acoustic target signal exceeding said thresholdamplitude, to continue control of said torpedo steering means by saidgyro-actuated switches until operation of said second switch means toits second condition; and means for thereafter holding said secondswitch means in its second condition, said second switch means thenconnecting the solenoids in circuit with the first switch means forexclusive control thereby to eiect torpedo steering in 'accordance withoperation of saidrst switch means to its rst and secondeonditions bysaidYelectro-acoustic means.

2. A combination as defined in claim 1, including a pair ofserially-connected capacitors, wherein said elect-roacoustic meansprovides a pair' of DC. signals having amplitudes differing in`accordance with the sense and extent of target Vdirection deviation fromtorpedo heading, andapplies Said DC. signals individually to saidcapacitors to provide a summation signal across said pair of capacitorscorresponding in Apolarity and magnitude to the sense land extent ofsaid target direction deviation, and means utilizing said summationsignal for actuation of said first switch means.

3. In combination with a propulsive torpedo: torpedo steering means;course gyroscope means for controlling said torpedo steering means inaccordance with deviation of said torpedo from a predetermined course;electroacoustie means for sensing acoustic target signals and forcontrolling said torpedo steering means in accordance with thedirection, relative to torpedo heading, of the target which gives riseto said vacoustic target signals; intensity switch means; saidelectro-acoustic means further operating said intensity switch meansfrom a rst condition to a second condition in response to sensing anacoustic target signal exceeding a predetermined threshold amplitude; anenabler switch; initial run control means for operating said enablerswitch from a rst condition to a second condition after expiration of lapredetermined torpedo run interval; said enabler switch in its first'condition connecting said torpedo steering means inV circuit with saidcourse gyro means forexclusive control thereby until expiration of saidpredetermined interval; said enabler switch in its second conditionconnecting said torpedo steering means in circuit with said course gyromeans, through saidintensity switch means in its iirst condition tocontinue control by said course gyro means until operation of saidintensity switch means to its second condition in response toIaniacoustic target signal exceeding said threshold amplitude; and meansfor thereafter holding said intensity switch means in its secondcondition, saidV intensity switch means then connecting said torpedosteering means in circuit with said electroacoustic means for exclusivecontrol thereby.

References Cited in the tile of this patent v UNITED STATES PATENTSRobinson Mar. 25, 1952

